Various fluids may be used as part of the process of drilling an oil or gas well. Such fluids can serve a variety of purposes, such as lubrication, cooling, transport of particles generated by the drilling process, and maintenance of the stability of various subterranean formations surrounding the wellbore. In many instances, it can be desirable to flush hydrocarbons out of certain hydrocarbon-containing subterranean formations proximate to the wellbore. Certain drilling fluids can be used for such purposes.
In many instances, it may be desirable to remove such fluids from the formation following their introduction. This can be done through the use of fluid loss control pills. Or, in some other examples, waterborne natural and synthetic polymers can be used, such as guar gum, celluloses (e.g., carboxymethylcellulose, hydroxyethylcellulose, and the like), polyacrylamides, hydrolyzed polyacrylamides, and the like. These compounds are prone to breakdown, however, which may tend to limit their utility in wellbore applications.
Aqueous viscoelastic surfactants offer a partial potential solution. But such compounds may yet break down when exposed to hydrocarbon fluids. Inducing polymerization of the surfactant compounds can remedy some of these disadvantages. For example, one can employ 10-undecenoic acid derivatives as surfactant monomers, which, in turn, can undergo free-radical polymerization to form surfactant-polymer compounds. These compounds can be less susceptible to breakdown. However, in some instances, these compounds can have commercially unacceptable sphere-to-rod transition parameters. Therefore, there is a continuing need to develop new polymerizable aqueous viscoelastic surfactant compositions that may have properties that make their use more suitable as wellbore fluids.